Trolley for insertion and extraction plants of strings of drill pipes in production wells of hydrocarbons in general and plant equipped with said trolley

ABSTRACT

A trolley for transferring pipe stands ( 8 ) between the tower ( 1 ) and pipe rack ( 4 ) of a plant for the insertion and extraction of strings of drill pipes in production wells of hydrocarbons in general, wherein said trolley comprises a movable slide ( 21 ), relating to the same trolley ( 10 ), between a boost direction (F 2 ) of said pipe stands ( 8 ) towards the tower ( 1 ) and a pulling direction (F 1 ) of the same pipe stands ( 8 ) from the tower ( 1 ) towards the pipe rack ( 4 ) of said plant. 
     With respect to known trolleys used in plants for the insertion and extraction of pipes in production wells of hydrocarbons in general, that according to the present invention offers the advantage of operating exclusively by gravity in transporting pipe stands, whose weight serves for maintaining their correct transfer position.

The present invention relates to a trolley for insertion and extraction plants of strings of drill pipes in production wells of hydrocarbons in general.

The field of the invention relates to the production of gaseous or liquid hydrocarbons in general, extracted from the respective wells using strings of pipes (“tubing”) suitably assembled, connecting the single pipes with a head/tail coupling until the length necessary for reaching the production area or reservoir has been covered.

This type of processing envisages the cyclic insertion and extraction of strings of pipes from the production well by means of a work-over rig, in order to allow both ordinary maintenance interventions and also for restoring the production activity. These insertion operations of drill strings are effected by connecting or joining single pipes having a standard length of about 9 m, with a threaded head-to-tail coupling. In the extraction phase of the strings, the same pipes, however, are disconnected or separated from each other in correspondence with the same threaded couplings.

Consequently, the extraction and insertion movements of the strings must be interrupted, at every interval of 9 meters of pipe, for the time necessary for unscrewing and screwing the threaded connection couplings between adjacent pipes. These interruptions, however, are undesired as they negatively affect the production recovery, causing additional operational costs and loss of production. In the known art described above, the time necessary for transferring the single 9 meter drill pipes from the pipe rack to the work-over rig also contributes to increasing the interruption times of the production activity of the well.

In order to overcome these drawbacks, plants are known in which at least two single pipes are reciprocally joined, with a head-tail coupling, outside the rig. In this way, longer pipe stands are obtained with respect to standard stands, which allows the dead times of the extraction unit to be reduced ((Aaron Sinnott: “Taking tubulars offline—Reprinted from Oilfield Technology”—30 Sep. 2013, XP055207318).

In moving pipe stands composed of two or more pipes having a standard length, the problem arises, however, of availing of a suitable transportation trolley, which is suitable for moving and supporting pipes having a greater length and weight with respect to standard values.

The main objective of the present invention is therefore to provide a trolley for insertion and extraction plants of strings of drill pipes in production wells of hydrocarbons in general, wherein the above-mentioned trolley is suitable for transferring the mentioned pipe stands from and towards the pipe rack and work-over rig.

This and other objectives are achieved by means of the trolley and plant of claims 1 and 7 respectively. Preferred embodiments of the invention can be found in the remaining claims.

With respect to known trolleys used in plants for the insertion and extraction of pipes in production wells of hydrocarbons in general, that according to the present invention offers the advantage of allowing the safe movement of pipe stands having greater lengths and weights with respect to those used in this type of application.

The trolley of the invention also offers the advantage of operating exclusively by gravity in the transportation of pipe stands, whose weight serves for maintaining their correct position during the transfer.

This solves the problem of safely and simply moving pipe stands from and towards the plant, without the help of complex hydraulic systems for holding them in the correct transfer position.

These and other objectives, advantages and characteristics appear evident from the following description of a preferred embodiment of the trolley and plant of the invention, illustrated, for non-limiting purposes, in the figures of the enclosed drawings.

In the same:

FIGS. 1 to 4 illustrate the plant of the invention;

FIG. 5 illustrates the layout of the logistic connection, separation and control pole of the pipes;

FIG. 6 illustrates a perspective view of the trolley for moving pipe stands used in the plant of FIGS. 1 to 4;

FIG. 7 illustrates a perspective view of a detail of the slide of the trolley of FIG. 6;

FIG. 8 illustrates a detail of the pulling fork assembled on the slide of FIG. 7;

FIG. 9 illustrates the slide of FIG. 7 without the fork of FIG. 8;

FIG. 10 illustrates the detail of the male of a pipe stand moved with the trolley of the previous figures;

FIG. 11 illustrates the trolley of FIG. 6 in a front view;

FIG. 12 illustrates the trolley of FIG. 6, in a longitudinal section, in the boost phase of the pipe stands of FIG. 10;

FIG. 13 illustrates a perspective and sectional view of the trolley of FIG. 12;

FIG. 14 illustrates the trolley of FIGS. 12 and 13 in the initial boost phase of the pipe stands;

FIGS. 15 and 16 illustrate the trolley of FIG. 6, in a longitudinal and perspective section, during the pulling phase of the pipe stands of FIG. 10;

FIGS. 17 to 19 illustrate a perspective view of the trolley of FIG. 6, in different transporting positions of the pipe stands on the guide of the pipe rack; and

FIG. 20 illustrates an exploded view of the trolley of the invention.

As illustrated in FIG. 1, a work-over rig comprises a tower 1 equipped with a travelling block 2, to which the pipe stands 8 consisting of a plurality of single joints 3 are connected, in turn removed from a pipe rack 4 and hoisted towards the rig floor 6 by sliding on a V-door 5.

In the example illustrated, the mentioned stand 8 is obtained by the coupling of two pipes 3 a and 3 b in correspondence with the connection 22 of FIG. 1, but it is understood that the invention is not limited to the number of pipes forming the mentioned stand 8.

After assembling the pipes 3 a and 3 b on the pipe rack 4, the stand 8 thus obtained is hoisted, by means of the travelling block 2, onto the rig floor 6, so that it can be coupled with the stand 9 already in the well (FIG. 4).

According to the invention, in order to facilitate the transfer of the stands 8 from and towards the rig floor 6, at least one trolley 10 is advantageously used, that can be moved by means of a chain 11 (FIG. 2), or with equivalent systems (hydraulic or mechanical systems), not shown.

The management of the plant of the previous figures can be effected according to the scheme of FIG. 5. In the same, a certain number of work-over rigs, 16, 17, 18 is served by an assembly and disassembly station 19 of the stands 8 outside the same rigs. The transportation of these stands from the station 19 to the same rigs 16-18 is effected with the help of special means 20.

The trolley 10 of the invention, as represented in FIGS. 6 to 9 and 20, comprises an external carter 12, substantially U-shaped, overturned over a guide 13 for transporting the pipe stands .8 onto the pipe rack 4.

The trolley 10 is equipped with the slide 21 of FIG. 7, in turn composed of the sliding base 22 of FIG. 9, on which the pipe stand 8 rests. The above-mentioned base 22 is, in turn, completed by the fork 23 of FIG. 8, whose arc-shaped bottom 24 is removably housed in the corresponding seat 25 of the base 22 of FIG. 9. Thanks to this embodiment, the dimensions of the forks 23 can be selected in relation to the diameter of the pipe stand 8 in FIG. 10.

The slide 21 also comprises a plate 26, destined for receiving the thrust of the tool joint 31 of the pipe stand 8 during their transportation towards the tower 1. The same slide 21 of the trolley 10 is, in turn, slidingly supported above a corresponding guiding channel 35 (FIGS. 13, 19).

As better illustrated in FIGS. 12 and 16, the plate 26 of the slide 21 is equipped with a transversal pin 27 slidingly guided in the direction of the arrows F1 and F2 inside slots 28 positioned on the side walls of the same carter 12 (FIGS. 17 and 18). The movement of the slide 21 in the direction of the arrow F1 of FIG. 16 is effected in contrast with the action of a spring 29 interposed between said plate 26 and a fixed shoulder 30 of the same carter 12.

In the boost phase towards the tower 1 of the pipe stand 8, in the direction of the arrow F2 of FIGS. 12 to 14, the plate 26 pushes against the tool joint 31 of the above-mentioned pipe stand 8, crushing the spring 29 until it interferes against the shoulder 30. In this way, the pipe stand 8 is caused to slide above the guide 13, in the direction of the tower 1. The movement of the slide 21 on the guide 13 is advantageously effected with the help of rolls 32, in turn sliding on respective rails 33 of the same guide 13 (FIG. 19).

In the contrary movement of the slide 21, arrow F1 of FIGS. 15 and 16, the fork 23 grips the shoulder 34 of the tool joint 31 of FIGS. 10, 15 and 16. In these conditions, the position of the plate 26 of the slide 21 corresponds to the rest position of the spring 29. With this movement of the slide 21, the pip stand 8 is removed from the tower 1 in the direction of the outlet of the pipe rack 4. 

1. A trolley for transferring pipe stands (8) between the tower (1) and pipe rack (4) of a plant for the insertion and extraction of strings of drill pipes in production wells of hydrocarbons in general, characterized in that it comprises a movable slide (21), relating to the above-mentioned trolley (10), between a boost direction (F2) of the above-mentioned pipe stands (8) towards the tower (1) and a pulling direction (F1) of the same pipe stands (8) from the tower (1) towards the pipe rack (4) of said plant.
 2. The trolley according to claim 1, characterized in that said slide (21) comprises a supporting base (22) of said pipe stands (8).
 3. The trolley according to claim 2, characterized in that said slide (21) comprises an engagement fork (23) with said pipe stands (8), said fork (23) being removably assembled inside a corresponding seat (25) of said base (22).
 4. The trolley according to claim 3, characterized in that it also comprises a carter (12) having side slots (28), said slide (21) also comprising a transversal pin (27) passing through said slots (28) and sliding in the direction of said arrows (F1,F2).
 5. The trolley according to claim 4, characterized in that it comprises a fixed opposing shoulder (30) for a thrust spring (29) of said plate (26).
 6. The trolley according to claim 5, characterized in that it comprises sliding rolls (32).
 7. A work-over rig for the insertion and extraction of strings of drill pipes in production wells of hydrocarbons, comprising a tower (1), a rig floor (6) and a pipe rack (4) for pipe stands (8) obtained from the assembly of at least two single pipes (3 a, 3 b) having a standard length, effected prior to the transfer of the same pipe stands (8) to said tower (1), characterized in that it is equipped with a trolley (10) according to claim
 1. 8. The plant according to claim 7, characterized in that it comprises a supporting guide (13) for sliding rails (33) of the trolley (10) in correspondence with its rolls (32), a channel (35) also being envisaged for guiding said base (22).
 9. The plant according to claim 8, characterized in that said assembly of at least two single pipes (3 a, 3 b) is effected on the above-mentioned pipe rack (4), the stand (8) thus obtained being hoisted on said rig floor (6) and being subsequently coupled with the stand (9) already inserted in the well.
 10. A management system of the plant according to claim 1, characterized in that it comprises a servo-station (19) of at least one work-over rig (16,17,18), the same station (19) effecting the assembly and disassembly of said stands (8) outside the at least one rig (16,17,18). 